Brocade introduced this switch in September 2013. It has speed and feeds that are reminiscent of the Broadcom Trident+ family of products, but this is not yet-another Trident clone. It is a single chip monolithic switch with 24 MBytes of integrated packet buffer memory. I suspect the reason Brocade may have cooked up a custom chip rather than using merchant silicon is because the VDX family sports TRILL for its data center fabric. TRILL is not part of the commonly available feature set in merchant silicon.
The switch is available in 48-port SFP+ and 48-port twisted pair Ethernet variants. Brocade has a version that license-locks the port speeds to 1 Gb/s until you send them more money. They call this pay as you grow. For both models, the uplink ports are QSFP 40 Gb/s.
Nick Lippis, one of the for-hire switch testers, had the 6740 run through its paces. Registered users can get a copy of the report in PDF format, but you can listen to exactly the same content either on youtube or in podcast format. The report shows a switch that is line-rate on all ports at all packet sizes but does not measure capability to absorb microbursts except to mention the total amount of packet buffer without saying anytbing about how it is used. Fortunately, email from TAC says more than Lippis' 33 page report.